Abstract: The predicting method for conventional production indexes (PI) has good effect on the new wells in new blocks. As the old block has been produced for a long time, the oil characteristics and other parameters of the block change greatly. As a result, the use of conventional PI predicting method is limited and the predicting results are not so accurate. Based on the pseudo-steady production capacity equation of circular closed reservoir, combined with the production data of oilfields, a new predicting method is developed. Also, the result based on the new method is compared with that of the conventional one, which shows that the new method is more accurate.