The invention provides a portable detection device and a portable detection method based on a neuromuscular electric stimulation device. The portable detection device comprises a housing, a circuit board, a software system, and a touch screen. The housing comprises a main housing body, key caps, and installation fixing members. The circuit board comprises a relay network, a resistor network, a signal conditioning circuit, a CPU single-chip microcomputer, and a power supply module. By adopting the automatic control, the safety protection, and the circuit conversion of the relay network, the switching of the load resistors having different resistance values of the resistor network, the amplification of the signals of the signal conditioning circuit, and by additionally providing a signal zero point circuit, sampling precision and sampling stability are improved, precision of detected electric parameters and waveforms is higher, and linear errors are reduced. The portable detection device has a simple structure, and is widely used in a medical device detection field and an industrial control field.