A method using an observed time difference of arrival for positioning a mobile station, comprising: transmitting to a mobile station an observed time difference of arrival, OTDOA, capability request message to inquire about a communication system technology supported by the mobile station and signal reception quality of each base station of a communication system supported, wherein the OTDOA capability request message comprises a plurality of communication system technologies existent in a current service area of the mobile station and corresponding signal reception quality information, provided for the mobile station to select based on the communication system technology supported by the mobile station; receiving an OTDOA support capability message returned by the mobile station, wherein the OTDOA support capability message comprises the communication system technology supported by the mobile station and corresponding signal reception quality; and selecting, according to the communication system technology supported by the mobile station and the corresponding signal reception quality, a base station for positioning the mobile station; sending to the mobile station auxiliary positioning information based on the communication system technology supported by the mobile station and the corresponding signal reception quality, wherein the auxiliary positioning information comprises identifications of cells in which the mobile station needs to receive a positioning reference signal, frequency points and positioning reference signal configuration information of these cells, so that the mobile station reports a measurement result based on the auxiliary positioning information; and using the measurement result to position the mobile station. transmitting to a mobile station an observed time difference of arrival, OTDOA, capability request message to inquire about a communication system technology supported by the mobile station and signal reception quality of each base station of a communication system supported, wherein the OTDOA capability request message comprises a plurality of communication system technologies existent in a current service area of the mobile station and corresponding signal reception quality information, provided for the mobile station to select based on the communication system technology supported by the mobile station; receiving an OTDOA support capability message returned by the mobile station, wherein the OTDOA support capability message comprises the communication system technology supported by the mobile station and corresponding signal reception quality; and selecting, according to the communication system technology supported by the mobile station and the corresponding signal reception quality, a base station for positioning the mobile station; sending to the mobile station auxiliary positioning information based on the communication system technology supported by the mobile station and the corresponding signal reception quality, wherein the auxiliary positioning information comprises identifications of cells in which the mobile station needs to receive a positioning reference signal, frequency points and positioning reference signal configuration information of these cells, so that the mobile station reports a measurement result based on the auxiliary positioning information; and using the measurement result to position the mobile station.