The invention discloses a method for preventing accidental movement of an elevator car and a control module operating based on the method. A sensing system and a braking system of an elevator are additionally arranged or transformed based on an original elevator control system structure, so that when the elevator moves accidentally, a reasonable braking scheme can be obtained according to the accidental movement condition, namely the condition of overspeed movement of the elevator and accidental movement of the elevator on a flat platform, and then the safety of equipment and the life and property safety of people are guaranteed. In this way, an original elevator system structure is not changed much, cost increase is low, and accidental movement of the elevator car can be effectively prevented.