Abstract: Pseudo-stochastic pulses can improve the accuracy of LEO reduced-dynamic orbit determination effectively, but the pseudo-stochastic pulse priors (i.e., time interval and a priori sigma) will affect the values of pseudo-stochastic pulse, thereby affecting orbit accuracy. In this paper, single-day GRACE orbit experiments based on reduced-dynamic method show that time interval decreases from 240 min to 6 min, a priori sigma increases from 1×10^-4 mm/s to 1×10^-1 mm/s, the total values of pseudo-stochastic pulse increases from 1×10^-2 mm/s to 1×10¹ mm/s, and the orbit accuracy improves from tens of centimeters to 2 cm; when a priori sigma is greater than 1×10^-1 mm/s, a priori sigma continues to increase, the values of pseudo-stochastic pulse remain unchanged and the orbit accuracy unimproved. Therefore, for single-day orbit solution, time interval is reduced to 6 min, a priori sigma goes up to 1×10^-1 mm/s, the values of pseudo-stochastic pulse increases, the orbit accuracy improves; a priori sigma continued to increase, the values of pseudo-stochastic pulse keep unchanged, and the orbit accuracy is unimproved. Using Swarm orbit experiments of different heights can be used to verify the validation of the conclusion.