This paper mainly discusses some issues of"Yinwei(因為)NP,Suoyi(所以)VP"construction such as the semantic features of NP,its encoding and decoding mechanisms and the relevant construction family.It is found that almost all the semantic types of NP can enter into this causal construction.On one hand,its encoding is related with the factors of causative event,cognitive processing mode,new-old information and foregroundbackground arrangement.On the other hand,its decoding is related with the cooperative principle and referential cohesion.At last,we discuss the relevant construction family of"Yinwei X,Suoyi Y".