In response to the high-precision maintenance requirements for large-sized space deployable masts in orbit，amulti-factor assembly precision analysis method considering hinge clearance and rod length deviation is proposed.An equivalent model for rotational pair clearance based on the massless rod principle is established，and a deployable mast motion model incorporating rod length deviation is constructed based on the Denavit-Hartenberg （D-H） theory.The Monte Carlo method is used for the multi-factor error simulations，yielding the ranges of hinge clearance adjustment and rod length deviation that meet the assembly accuracy requirements.Experimental results indicate that the proposed method effectively ensures the deploy ability and assembly precision of the deployable mast.