A method of a terminal measuring a reference signal for positioning in a wireless communication system, the method comprising: receiving assistant data related to a plurality of cells including a reference cell and one or more neighbor cells for positioning; calculating a reference signal time difference, RSTD, measurement value using a positioning reference signal, PRS, of the plurality of cells and a cell-specific reference signal, CRS, of the plurality of cells based on the assistant data; and reporting the RSTD measurement value to a location server the method characterized in that the assistant data includes number of CRS antenna ports information, CRS cyclic prefix, CP, length information, or multicast broadcast single frequency network, MBSFN, subframes configuration information of the plurality of cells, wherein in a state in which the assistant data related to a specific cell among the plurality of cells does not include number of CRS antenna ports information and the CRS is used for the RSTD measurement value, the terminal only utilizes antenna port 0, wherein in a state in which the assistant data related to the specific cell among the plurality of cells does not include CRS cyclic prefix, CP, length information, a CP length of the CRS used for the RSTD measurement value is considered identical to a CP length of the PRS, and wherein in a state in which the assistant data related to the specific cell among the plurality of cells does not include multicast broadcast single frequency network, MBSFN, subframes configuration information, the CRS used for the RSTD measurement is all or a part of OFDM symbols of index = 0, 1, 4, 7, 8, and 11. receiving assistant data related to a plurality of cells including a reference cell and one or more neighbor cells for positioning; calculating a reference signal time difference, RSTD, measurement value using a positioning reference signal, PRS, of the plurality of cells and a cell-specific reference signal, CRS, of the plurality of cells based on the assistant data; and reporting the RSTD measurement value to a location server the method characterized in that the assistant data includes number of CRS antenna ports information, CRS cyclic prefix, CP, length information, or multicast broadcast single frequency network, MBSFN, subframes configuration information of the plurality of cells, wherein in a state in which the assistant data related to a specific cell among the plurality of cells does not include number of CRS antenna ports information and the CRS is used for the RSTD measurement value, the terminal only utilizes antenna port 0, wherein in a state in which the assistant data related to the specific cell among the plurality of cells does not include CRS cyclic prefix, CP, length information, a CP length of the CRS used for the RSTD measurement value is considered identical to a CP length of the PRS, and wherein in a state in which the assistant data related to the specific cell among the plurality of cells does not include multicast broadcast single frequency network, MBSFN, subframes configuration information, the CRS used for the RSTD measurement is all or a part of OFDM symbols of index = 0, 1, 4, 7, 8, and 11.