The invention discloses a dual-chip acoustic surface wave passive wireless temperature measuring sensor and a temperature measuring method thereof. The sensor comprises two resonant acoustic surface wave sensor chips which are in parallel connection; one resonant acoustic surface wave sensor chip has a positive temperature coefficient, and the other resonant acoustic surface wave sensor chip has anegative temperature coefficient. According to the dual-chip surface acoustic surface wave passive wireless temperature measuring sensor and the temperature measuring method thereof, the difference value of the resonance frequencies of the two chips and the temperature have a linear relationship, the temperature value is figured out accordingly, the situation that the initial frequency change iscaused by the change of environmental conditions, so that the initial temperature change is caused can be avoided, and the temperature measuring accuracy can be improved.