The lasercom optical-terminal performance testing platform (LCOT-PTP) is a precision optical system providing experimental testing of important characteristic parameters including transmitting power, beam divergence angle, far-field spot energy distribution and coaxialities of different branches in a lasercom optical terminal (LCOT). The LCOT-PTP consisting of a telescope, beam splitters, a receiving branch, a transmitting branch and a tracking test branch is developed. Due to the testing process requirements in coarse tracking, fine tracking and the assembly integration, the working wavelengths of 808nm, 1550nm and 632.8nm are adopted in testing-system design. By using the under-test LCOT parameters and Gaussian beam transmitting theory, the optical-system design is completed. Based on the established LCOT-PTP, the key performance testing work is accomplished. © 2020 Elsevier GmbH