The invention discloses a multifunctional digital display refractometer, comprising a housing, a circuit board, a built-in power supply, and a light path sensing system, wherein the circuit board is arranged inside the housing; a microcontroller and a display module are arranged on the circuit board; the built-in power supply is arranged inside the housing and is connected with the circuit board; the light path sensing system is arranged inside the housing and comprises a bracket, an inverted trapezoidal prism, a measuring reservoir, a light-emitting diode (LED) lamp, and a complementary metal-oxide-semiconductor transistor (CMOS) photoelectric sensor; the bracket is arranged at one side of the circuit board; the inverted trapezoidal prism is arranged on the bracket; the measuring reservoir is arranged at the top surface of the inverted trapezoidal prism; the LED lamp is arranged at one side of the inverted trapezoidal prism and on the bracket; the CMOS photoelectric sensor is fixed on the bracket and arranged at the other side of the inverted trapezoidal prism and is in communication connection with the microcontroller. The refractometer disclosed by the invention is high in accuracy and low in cost, and the accuracy of the refractive index is 0.00005.