The high-energy photon source (HEPS) is a 6-GeV ultralow emittance synchrotron radiation light source being built in China. The HEPS global timing system has been designed using MicroTCA.4 based event timing technologies. A prototype bench test system has been developed, and some critical parameters of the timing system have been tested and confirmed using this prototype system. This report gives a short introduction to the current status of the HEPS global timing system. It also presents an R&D work of designing a MicroTCA.4 timing card, called IAMC-TIMR1.