There is a lack of a universal and readily integrable online measurement and compensation scheme for six-degree-of-freedom (6-DOF) errors along the Z-axis of micro-nano coordinate measuring machines (CMMs). To address this challenge, this study introduces a synchronous measurement method for the axis of micro Z-axis linear and angular errors based on laser interferometry and autocollimation principles，and establishes a spatial error compensation model under Z-axis 6-DOF influence based on the Abbe principle and the Bryan principle. An in-situ and on-line Z-axis 6-DOF error measurement system based on the measurement method was developed and applied to a micro-nano CMM. Measurements were performed along the Z-axis on a grade 0 gauge block with a nominal thickness of 8 mm using the CMM. The results show that the measurement standard deviation and indication error are reduced by 54.6% and 54.3%, respectively, after compensation. This method, compensation model and the system provide a reliable solution for improving the measurement and machining accuracy of coordinate measuring machine(CMM) and other precision equipment.