A method for transmission parameter determination, comprising: determining , by a terminal device, a first transmission parameter according to a channel busy ratio, CBR, and a priority of a service to be transmitted; and sending , by the terminal device, the service to be transmitted using the first transmission parameter; wherein the first transmission parameter comprises at least one of a modulation and coding scheme, MCS, range or a physical resource block, PRB, number range, and a second transmission parameter comprises at least one of an MCS range or a PRB number range, the first transmission parameter and the second transmission parameter belonging to different versions of a communication protocol, wherein the method further comprises: acquiring, by the terminal device, at least one proportion coefficient, the at least one proportion coefficient being configured by a network device or preconfigured in the terminal device, wherein determining , by the terminal device, the first transmission parameter according to the CBR and the priority of the service to be transmitted comprises: determining, by the terminal device, the second transmission parameter according to the CBR and the priority of the service to be transmitted; and multiplying, by the terminal device, the second transmission parameter using the at least one proportion coefficient to obtain the first transmission parameter. determining , by a terminal device, a first transmission parameter according to a channel busy ratio, CBR, and a priority of a service to be transmitted; and sending , by the terminal device, the service to be transmitted using the first transmission parameter; wherein the first transmission parameter comprises at least one of a modulation and coding scheme, MCS, range or a physical resource block, PRB, number range, and a second transmission parameter comprises at least one of an MCS range or a PRB number range, the first transmission parameter and the second transmission parameter belonging to different versions of a communication protocol, wherein the method further comprises: acquiring, by the terminal device, at least one proportion coefficient, the at least one proportion coefficient being configured by a network device or preconfigured in the terminal device, wherein determining , by the terminal device, the first transmission parameter according to the CBR and the priority of the service to be transmitted comprises: determining, by the terminal device, the second transmission parameter according to the CBR and the priority of the service to be transmitted; and multiplying, by the terminal device, the second transmission parameter using the at least one proportion coefficient to obtain the first transmission parameter. acquiring, by the terminal device, at least one proportion coefficient, the at least one proportion coefficient being configured by a network device or preconfigured in the terminal device, wherein determining , by the terminal device, the first transmission parameter according to the CBR and the priority of the service to be transmitted comprises: determining, by the terminal device, the second transmission parameter according to the CBR and the priority of the service to be transmitted; and multiplying, by the terminal device, the second transmission parameter using the at least one proportion coefficient to obtain the first transmission parameter. determining, by the terminal device, the second transmission parameter according to the CBR and the priority of the service to be transmitted; and multiplying, by the terminal device, the second transmission parameter using the at least one proportion coefficient to obtain the first transmission parameter. <EOS>