Abstract: Aiming at the shortcomings of traditional buried long-term Cu/CuSO4 reference electrode, such as short service lifetime and fragile, an all-solid-state electrolyte Cu/CuSO₄ reference electrode was developed. The micro morphology, element distribution and structure of the all-solid-state electrolyte were analyzed through scanning electron microscopy (SEM), energy disperse spectroscopy (EDS) and mercury porosimetry. The properties of the reference electrode were studied by electrochemical test, ion diffusion test and electrode buried test. The results showed that the all-solid-state electrolyte formed a dense microporous structure. The electrode had good potential stability and anti-polarization performance. The temperature coefficient of the electrode was 0.862 mV/℃. The copper ion loss rate of the electrode was only 1/3 of that of the traditional Cu/CuSO₄ reference electrode. The reference electrode had good performance in soil environment, so it can be applied to engineering.