A locating device comprises a matrix and a pin component arranged on the matrix and further comprises a drive part. Accommodation portions are formed in the matrix. The pin component comprises a pin sleeve fixed on the matrix and a pin penetrating the pin sleeve. The pin sleeve comprises a locating sleeve with expansion grooves, and the pin penetrates the locating sleeve to form an inclined face. The drive part is accommodated in the accommodation portions and is connected with the accommodation portions. An air inlet communicated with the accommodation portions is formed in the matrix, an air inlet channel communicated with the accommodation portions is formed in the pin axially, and a plurality of through holes are formed in the periphery wall of the pin at intervals along the radial direction and penetrate the side wall of the pin respectively to be communicated with the air inlet channel of the pin. By means of the location device, the locating accuracy can be improved, impurities remaining on the outer surface of the pin can be blown away, and effects of impurities on work-piece locating accuracy are prevented. The invention further provides a locating method using the locating device.