The most common failure of the liquid oxygen pump is the leakage of the seal. For the structure of mechanical seal, the key is the bad contact of the sealing surface of the dynamic and static ring of the friction pair. It is related to the grinding quality of sealing surface, the assembling quality of pump shaft and bellows, and the material of friction pair. For the labyrinth type seal structure, it is related to the adjustment of the seal clearance and the pressure of the seal gas. Other faults and solutions are as follows: 1) the pump can't start: the current is blocked. The circuit should be rechecked to switch on the current; the rotor gets stuck or the gap is too small. The pump should be removed for inspection and the clearance should be adjusted. 2) no drainage after starting: the steering of the pump is opposite. Check the motor steering, change the power wiring; the pump is not fully precooled, gas is generated. The pump should be stopped and fully precooled again; the inl...