Potato biscuit was prepared by two-step baking process with fresh potato as major raw material. The effects of the ratio of mashed potato to low-gluten flour, the ratio of ammonium bicarbonate to sodium bicarbonate, and the ratio of liquid whole egg to palm oil, on the shearing force, color difference and sensory score of biscuits were studied. The results showed that when the ratio of mashed potato to low-gluten flour was 13:2, the ratio of ammonium bicarbonate to sodium bicarbonate was 5:2, and the ratio of liquid whole egg to palm oil was 5:5, the shear forces of potato biscuits were in the range of 2000~2500 g, and the sensory scores of potato biscuits were higher than 80. Based on the results, through the three-factor and three-level response surface methodology optimization, the optimal formula of biscuit was obtained as follows: potato 55.00%, low-gluten flour 20.00%,ammonium bicarbonate 0.50%, sodium bicarbonate 0.13%, liquid whole egg 6.86%, palm oil 5.00%, sugar 6.82%, light cream 5.69%. The potato crisp biscuit under this formula had good potato flavor, crisp taste and good quality, with the sensory score of 87.20. It was consistent with the predicted value of the response surface model. The study could be used as theoretical basis for the development of potato baking product.