With the gradual growth of family businesses in Taiwan, the structure of family organizations has become increasingly complex. How to balance family governance and corporate governance in the family firm is an important issue. Will family members be the resistance or help of family firm? This research use the sociemotional wealth theory framework to consider that whether family firms choose diversification strategies to protect SEW. The study found that the stronger Emotional Attachment of Family Members, the more the family firm tends to diversify operations. And the study also found that the second and third generations of family members have a greater impact on diversification. Finally, this study divides the sample into two categories based on the size of the company. The results of the study found that as the size of the company increases, in order to protect SEW, the greater Family Control and Influence , the less tend to diversification. When the Emotional Attachment of Family Members is stronger and the willingness of Renewal Family Bonds Through Dynastic Succession is higher, the firm tends to diversification.