The invention discloses a mobile terminal and a signal processing method, a baseband chip and a radio frequency chip of the mobile terminal. The mobile terminal comprises the baseband chip and the radio frequency chip. In the radio frequency chip, radio frequency modules of all communication modes share oscillator signals generated by a crystal oscillator. In the baseband chip, according to the frequency shift between local carriers and corresponding base station signals, sampling modules corresponding to the radio frequency modules are used for conducting phase compensation on communication signals so as to obtain signals to be sent, actually, reverse phase consumption is conducted on all the communication signals first according to frequency shift, consequently, frequency synchronism between output signals of the baseband chip after reverse phase compensation and after being modulated with the local carriers generated by the oscillator signals and corresponding base station signals is realized. The mobile terminal and the signal processing method, the baseband chip and the radio frequency chip of the mobile terminal reduce the cost and the power consumption of the radio frequency chip in the multi-mode mobile terminal and the cost and the power consumption of the baseband chip in the multi-mode mobile terminal, and eliminate the complex clock switching process.