Planetary system trajectory is inherently related to sun movement. Considering that planetary system movement affects solar activity and even global climate change, studies on its changing law and characteristic are of significance and values. In this study, the kinematic index of planet heliocentric longitude is created based on the orbital elements of planets in the solar system. Both the planet juncture index and heliocentric longitude are used to investigate the periodic planetary system movement around the barycentre of the solar system. The planet juncture index is the norm of the total quality-vector-weights for planetary system. It represents the distance between the barycentre of the planetary system and the sun. When all planets nearly align, the planet juncture index peaks; otherwise, it falls. The planet heliocentric longitude is the angle between the line from the projection of the barycentre of the planetary system onto the datum to that of the sun and the datum axis. The planet heliocentric longitude ranges from 0 to 2p. The planet juncture index and heliocentric longitude are two important kinematic indexes for researching the changing law and characteristic of planetary system movement. The former represents the distance between the barycentre of the planetary system and the sun and the degree of convergence and separation of the planetary system. The latter represents the exact location of the barycentre of the planetary system relative to that of the solar system. This study explores the changing rule and characteristic of planetary system movement through the two kinematic indexes. Results of this study bear significance and value on theories of studies on solar movement, solar activity and global climate change. The power spectrum analysis method is a spectral analysis indicating digital time-series in different frequencies of energy distribution, which reflects the distribution of power spectrum in different frequencies of stochastic signal. The implied periodic trends in the frequency domain are revealed with the power spectrum analysis method by analysing the character of signal and processing every coordinate time-series with Fourier transform. Both the planet heliocentric longitude and juncture index are studied through numerical simulation. The base data of the variations of planet juncture index and heliocentric longitude for nearly 2000 years are derived. The comparison between the base data of the two kinematic indexes show that both exhibit periodic trends and varying characteristics similar to those of the planetary system movement. The power spectra of results reveal that both the planet juncture index and heliocentric longitude are complicated, with remarkable periodicity parameters of 35.958, 19.873, 13.768 and 12.807 a for the former and 162.602, 29.446, 11.865, 8.457, 7.421 and 5.936 a for the latter. The most remarkable periodicity parameters are 19.873 and 11.865 a. To a certain extent, these periodic trends provide basis for analysing solar activity and global climate change. Planet juncture index indicates the moving pattern of the barycentre of the planetary system around that of the solar system and thus specify the moving pattern of the sun around the barycentre of the solar system. Planet heliocentric longitude indicates the accurate position of the barycentre of the planetary system relative to that of the sun and thus indicates the accurate position of the barycentre of the solar system relative to that of the sun. Both provide an effective means to investigate the relationship between sun movement and solar activity.