The existing portable spectrometer cannot measure the α-β-γ ray at the same time, which makes the evaluation and processing of the α-β-γ mixed scene inconvenient, so a portable α-β-γ spectrometer is developed to solve the problem. The spectrometer uses a PIPS detector and a LaBr3(Ce) detector to measure α-β particles and γ-rays, respectively, to obtain a high-resolution energy spectrum. The main properties of the spectrometer such as α energy resolution, α/β surface emissivity response, γ energy resolution and temperature stability were tested. The α energy resolution is less than 140 keV (5.486 meV, 0.1 atm), surface emissivity response of α particles is 67.34% (241Am), surface emissivity response of β particles is 19.13%(90Sr-90Y), and γ energy resolution is less than 3.4% (662 keV). Therefore, the spectrometer can simultaneously measure the α-β-γ rays and obtain the high resolution energy spectrum, which is helpful for the related personnel to make rapid and accurate evaluation and treatment of the measurement site.