Inthefinancingprocessofstart-ups，theobjectoffinancingandthedesignofcontractswillhavean important impact on the operating status of start-up enterprises and social welfare level. In this paper，the ob- jects of financing are divided into venture capitalists who merely pursue monetary income and strategic inves- tors who pursue both monetary returns and strategic objectives. Based on such classification，this paper studies the choice of financing objects and the design of financing contract among three financing methods: single in- vestor，multiple independent investors and syndicate in staged financing. Ultimately，the optimal financing de- cision for entrepreneurs is given when the primary goal is to social welfare optimization and the secondary target is to maximize an enterprise’s expected return. It is shown that an optimal financing decision should include the optimal financing method and the optimal financing object. In the case of financing approach，when a syn- dicate organization provides financing is feasible，the entrepreneur should seek syndicate financing and this fi- nancing method is always socially efficient; when it is not feasible，the entrepreneur should seek financing from multiple independent investors，however，this financing approach cannot achieve the optimal social wel- fare. Regarding the financing object，the entrepreneur should choose investors whose effort levels are the clo- sest to the first-order optimal effort level.