Owing to the existence of sulfur, a heavy atom, in the structure unit of PPS (C_6H_4S), P(r), the experimental reduced radial distribution function of its atomic-electronic density shows a group of finger print peaks in the range of 4—7 distinctly. According to the erystal structure model of PPS, an approximate P(r) curve is set up. Comparing it with the experimental results, we have discovered that the height of the 5th, 6th and 7th peak, which decreases with the decrease of sample erystallinity, is consistent with the damage of three interchain S—S distances (5.16 , 5.61, 6.76 ) in the erystal structure. And, correspondingly, the number of S—C distance is increased, which is consistent with the increase of the 4th and 7th peak height in the sample of noncrystalline state. The present authors hold that this is caused by the molecular chain displacement occurring along the direction of fibrous axis. The position of the 6th peak moving from 5.7 to 6.0 is referred obviously to the lateral space expansi Owing to the existence of sulfur, a heavy atom, in the structure unit of PPS (C_6H_4S), P (r), the experimental reduced radial distribution function of its atomic-electronic density shows a group of finger print peaks in the range of 4 -7 distinctly. According to the erystal structure model of PPS, an approximate P (r) curve is set up. Comparing it with the experimental results, we have discovered that the height of the 5th, 6th and 7th peak, which decreases with the decrease of sample erystallinity, is consistent with the damage of three interchain S-S distances (5.16, 5.61, 6.76) in the erystal structure. And, correspondingly, the number of S-C distance is increased, which is consistent with the increase of the 4th and 7th peak height in the sample of noncrystalline state. The present authors hold that this is caused by the molecular chain displacement occurring along the direction of the fibrous axis. The position of the 6th peak moving from 5.7 to 6.0 is referredarently to thelateral space expansi