In order to reduce launch mass and volume of the space telescope apparently, and to make it suitable for the vehicle requirements of the microsatellite, a new spontaneous deployment mechanism of the space telescope based on the lenticular tape springs was designed, which aimed at one optical system. Firstly, the geometrical sizes of the lenticular tape spring used in this article were preliminarily designated through theoretical analysis, and a new spontaneous deployment mechanism based on the lenticular tape springs was designed aimed at one space optical system. Secondly, the finite element model of the deployment mechanism was built, and its deployment characters were analyzed. Finally, the prototype of the spontaneous deployment mechanism was built up and the experiment was carried out to study its characters. Experimental results indicate that the deployment mechanism is 500 mm in height when it has deployed, and the repetitive deploy accuracy of it can be reached much less than 0.1 mm, also, the fundamental frequency is about 35.5 Hz when it has deployed. It can satisfy the deployment mechanism′s requirements of simple structure, low mass, steady and reliable deployment, as well as higher precision for space telescope.