In this paper we investigate the solvability of linear forward-backward stochastic differential equations (FBSDEs, for short). We give sufficient and necessary conditions of the solvability in linear forward-backward stochastic differential equations and prove it in a special case ($widehat A=O$). These results are extensional work of Ma & Yong (2000). Then we introduce the relationship between forward equation and backward equation, we also can get similar sufficient and necessary conditions to solve linear forward-backward stochastic differential equations by solving a matrix ordinary differential equation (a Riccati type equation).