Based on statistic data of fullness degree of Neogene lithologic reservoir in the Shijiutuo uplift，the size，distribution and controlling factors on fullness degree of trap were analyzed. The results show that there is a great variation in fullness degree of the lower Minghuazhen Formation. The vertical fullness degree of trap（ratio of oil column height to trap closure height）is between 16.1% and 87.5% with an average of 47.5%，while the areal fullness degree of trap（ratio of oilbearing area to trap closure area）is between 6.1% and 98.3% with an average of 52.6%. Sand bodies with vertical and areal fullness degree over 50% account for more than 1/2 of the whole sand bodies. The fullness degree of trap is unbalanced in the plane and different in the vertical and oil layer Ⅰ has the highest fullness degree of trap. The fullness degree of lithologic reservoir is mainly controlled by structural shape，sand body geometry，fault activity and fault-sand body contact length.The planar distribution of fullness degree of trap is controlled by structural shape. There is a negative correlation between sand body geometry amplitude，area，length-width ratio and fullness degree of trap. For sand body characterized by structural amplitude of less than 45 m，area of less than 4.5 km2 and length-width ratio of less than 4，more than 40% of its whole area is commonly filled by oil. For sand body whose contact length with fault is less than 4.5 km，more than 40% of its whole area is commonly filled by oil.