The invention relates to the technical field of electronic devices, in particular to a monocrystal oscillator electronic device and a method for determining frequency division coefficient. The device comprises at least two functional units which need different clock signals, a crystal oscillator and at least one adjustment circuit, wherein the crystal oscillator is used for generating a first clock signal and inputting the first clock signal to the functional unit which needs the first clock signal; each adjustment circuit comprises at least two phase-locked loops connected in cascade, and is used for adjusting the frequency and phase of the first clock signal step by step; after the adjustment, the first clock signal of which the frequency difference between the required clock signal and the first clock signal in different clock signals exceeds the set value, is obtained; and the adjusted clock signal is input to the functional unit which needs the adjusted clock signal. The invention can meet the clock signal requirements of multiple functional units by using only one crystal oscillator, and has the advantages of simple structure, small size and low cost.