China is becoming an ageing society. The social security system in urban China aims to protect the standard living of the elderly. However, the actuarial model predicts that the gender gap in pension benefits will tend to enlarge over the coming decades. This means that the female retirees are at a disadvantage in the distribution of pension benefits, compared with the male retirees. Using a regression analysis, I have studied the effect of factors on the pension gender gap. Besides gender discrimination, the other factors such as different retirement age, earnings, and education also have notable influences on gender differences in pension benefits. The results of this study suggest that the later Chinese pension reform should take account of the gender gap in pension benefits when proposing and implementing the new pension policies.