A mini-optical tweezer apparatus with the core function of a single optical trap was set up, which achieves the three dimensions capture of particles and the measurement of pN scale forces, without the traditional commercial microscope system. In this new system, the design of infinite optical imaging was adopted, and the semiconductor laser source and LED lighting were used to compact the structure of the machine. The micrometer 3-dimensional control platform can complete stable operations and quatitative measurements. With the fully closed optical path and integrating design, it becomes easier to adjust the machine and resist the external disturbance. This apparatus is compact and low costs so that it can be widely applied in the education of the mechanical effect of light, as well as scientific researches and applications of micrometer scale particles. In conclusion, the research and development of this independent optical tweezer apparatus will make contributions to the marketization of optical tweezer apparatus in the future.