Optical projection tomography (OPT) was developed in 2002 as a mesoscopic scale optical imaging technique. After then more researches were focused on imaging specimens between 1mm and 10mm. This technique was rapidly applied to gene expression, fluorescent immunohistochemistry and phenotype worldwide because of the features of high-resolution, no radiation and low-cost. However, the development of OPT is growing relatively slow. Further investigation of imaging systems and algorithms combining biological applications is needed to promote the research field of OPT in our country. In this paper, we investigated imaging systems and algorithms related with OPT, and developed a second generation of OPT system. We did the experiments of high-density tissue imaging and wide dynamic range sample imaging. The main contributions include: 1. The 2nd OPT system is developed. By hardware and software development, the system has a better system resolution, stability and convenience. System calibration section added, the software makes the experiment adjustment easier. 2. CT/ OPT imaging is used for high density samples. The method of OPT combined CT information and their optimal imaging time are discussed. For non-transparent samples, CT data before BABB transparency and OPT data after BABB transparency are fused to improve the image quality of high density and soft tissues. And single mode CT imaging, single mode OPT imaging and CT/ OPT imaging are compared to verify the imaging method. 3. OPT imaging of multi scale integration and virtual HDR is used for imaging of wide range sample. A high dynamic multi scale fusion OPT method is designed by switching different multi scale fusion approach using light and dark environment’s sample data. And to reduce the numbers of data acquisition, virtual HDR is used to divide the original data and recombined to the final result to improve the visual imaging effect.