The invention discloses a self-localization method of a sensor network node based on a smartphone. The method uses a general smartphone to replace a custom hardware module to be used as a network node, a plurality of mobile phone nodes orderly transmit linear frequency modulation (LFM) sound signals of 2k-6kHz by means of a loudspeaker and a microphone, and meanwhile, different mobile phone nodes sample the linear frequency modulation sound signals at a fixed frequency (44.1 kHz). Detection is performed on a sampling waveform by means of a generalized correlation method, and in view of a multipath effect, the self-localization method of the sensor network node based on the smartphone provided by the invention adopts a method of combining a threshold value method and time-frequency analysis to effectively inhibit the multipath effect, so that the arrival time of the linear frequency modulation sound signals can be obtained, then distance information between different nodes can be obtained, and finally, the unknown nodes can be located by adopting a multidimensional scaling (MDS) algorithm. The method of the invention does not need clock synchronization between the mobile phone nodes, and since the frequency is fixed, the arrival time of the sound signals can be accurately estimated through a sampling number; besides, the location accuracy is high, the cost is low, the networking is convenient and the prospect is wide.