The invention provides a refrigerant mass and flow measuring method and device and a measuring instrument. The method is used in a refrigerating system and comprises the steps that the evaporation pressure and the condensation pressure are obtained; the air suction temperature and the exhaust temperature of a compressor are obtained, and the compressor shell surface temperature, the environment temperature around the compressor and the compressor consumption power are obtained; the jetting temperature of an intermediate pressure container is obtained, and the oil content of a refrigerant mixture is obtained; a corresponding first enthalpy value, a corresponding second enthalpy value, a corresponding third enthalpy value, a corresponding fourth enthalpy value, a corresponding fifth enthalpy value, an enthalpy value difference and the heat exchange amount of the compressor and the outside environment are obtained through calculation according to the obtained various parameters; and according to the first enthalpy value, the second enthalpy value, the third enthalpy value, the fourth enthalpy value, the fifth enthalpy value, the enthalpy value difference, the heat exchange amount, the consumption power of the compressor and the oil content of the refrigerant mixture, the mass and flow of the refrigerant in the refrigerating system are obtained through calculation. According to the scheme, non-intrusive and high-precision measurement on the mass and flow of the refrigerant is achieved, bad influences brought to the refrigerating system in the measurement process are avoided, and the user experience is improved.