In the past researches, enterprise size was always benchmarked by its performance, however very few researches have been done on the influential factors regarding the enterprises' size to its executives' selection. At the same time, since many executives were promoted internally, does that mean whether the trust factor will motivate the selection decision is the main topic of this research. Through examination, the results are as follows: 1. The larger the size of the enterprise is, the more attention is paid to the executives' work attitude rather than management competency. 2. The smaller the size of the enterprise is, the more attention is paid to the executives' work attitude. 3. Trust factor will motivate enterprises' executive selection decision.