The invention relates to a portable NOx sampling device, comprising a gas control valve (2), a pressure gage (4) and a sampling gas circuit which are connected in the gas circuit in series; the sampling gas circuit comprises a gas flow rate regulating valve (8) which is connected with the pressure gage (4); the other end of the gas flow rate regulating valve (8) is connected with a three-way switching valve (9); the other two ends of the three-way switching valve (9) are respectively connected with the sampling circuit and a gas flow rate regulating circuit; a sampling disc (12) and a switching valve (13) are connected in series in the sampling circuit; the switching valve (13) and the gas flow rate regulating circuit are then respectively connected with the two ends of a three-way joint (14); and the other end of the three-way joint is connected with a gas flowmeter (15) and a gas accumulated flowmeter (16). The device is suitable for collecting NO2 and NO in hydrocarbon gas and is used for analyzing the content of NO2 and NO.