A transmission precoding matrix indication method, comprising: Receiving downlink control information from a network device, wherein the downlink control information comprises a resource allocation information indicator field, a transmission layer quantity indicator field, and a transmission precoding matrix indicator field corresponding to at least one subband, the resource allocation information indicator field is used to indicate a resource scheduled for uplink, the resource corresponds to the at least one subband, the transmission layer quantity indicator field is used to indicate an uplink transmission layer quantity, and a transmission precoding matrix indicator field corresponding to a subband is used to indicate an uplink transmission precoding matrix corresponding to the subband; characterized in that the method further comprises: determining a bit quantity of the transmission precoding matrix indicator field corresponding to the subband, wherein the bit quantity of the transmission precoding matrix indicator field corresponding to the subband is not greater than a preset total bit quantity of the transmission precoding matrix indicator field, a sum of bit quantities of all transmission precoding matrix indicator fields corresponding to all subbands is not greater than the preset total bit quantity, and the bit quantity of the transmission precoding matrix indicator field corresponding to the subband is related to a quantity of subbands corresponding to the resource scheduled for uplink; and determining the uplink transmission precoding matrix corresponding to the subband based on the bit quantity of the transmission precoding matrix indicator field corresponding to the subband and the uplink transmission layer quantity. Receiving downlink control information from a network device, wherein the downlink control information comprises a resource allocation information indicator field, a transmission layer quantity indicator field, and a transmission precoding matrix indicator field corresponding to at least one subband, the resource allocation information indicator field is used to indicate a resource scheduled for uplink, the resource corresponds to the at least one subband, the transmission layer quantity indicator field is used to indicate an uplink transmission layer quantity, and a transmission precoding matrix indicator field corresponding to a subband is used to indicate an uplink transmission precoding matrix corresponding to the subband; characterized in that the method further comprises: determining a bit quantity of the transmission precoding matrix indicator field corresponding to the subband, wherein the bit quantity of the transmission precoding matrix indicator field corresponding to the subband is not greater than a preset total bit quantity of the transmission precoding matrix indicator field, a sum of bit quantities of all transmission precoding matrix indicator fields corresponding to all subbands is not greater than the preset total bit quantity, and the bit quantity of the transmission precoding matrix indicator field corresponding to the subband is related to a quantity of subbands corresponding to the resource scheduled for uplink; and determining the uplink transmission precoding matrix corresponding to the subband based on the bit quantity of the transmission precoding matrix indicator field corresponding to the subband and the uplink transmission layer quantity. determining a bit quantity of the transmission precoding matrix indicator field corresponding to the subband, wherein the bit quantity of the transmission precoding matrix indicator field corresponding to the subband is not greater than a preset total bit quantity of the transmission precoding matrix indicator field, a sum of bit quantities of all transmission precoding matrix indicator fields corresponding to all subbands is not greater than the preset total bit quantity, and the bit quantity of the transmission precoding matrix indicator field corresponding to the subband is related to a quantity of subbands corresponding to the resource scheduled for uplink; and determining the uplink transmission precoding matrix corresponding to the subband based on the bit quantity of the transmission precoding matrix indicator field corresponding to the subband and the uplink transmission layer quantity.