Abstract: Differed from,The traditional method of force analysis of spatial mechanisms, this. Paper suggests a method of ;force analysis by; means of first determination of the, reaction acting at, one kinematic pair. This reaction is always statically determined for ordinally constrained mechanisms. In this paper the process of determination via matrices is given in detail. The four -link RCCC and five-link RRSRR mechanisms are analysed as examples. For RCCC mechanism the determination of other reactions acting at the remaining pairs and the determination of balancing force acting on the input or output link are given as well. This method of force analysis can be applied to any arbitrary complex spatial mechanisms.