Surface plasmon resonance (SPR) is an optical detection technology that has emerged in recent years. It mainly uses the evanescent field generated by the total reflection of the light wave to interact with the metal to perceive the refractive index change of the external medium. Theoretically, any phenomenon that causes a change in the refractive index can be detected using SPR. However, in practical applications, SPR sensors still have shortcomings, such as low sensitivity and weak detection signals, so the research on improving the detection sensitivity of SPR sensors has always attracted much attention. Graphene oxide, also regarded as the oxide of graphene, has optoelectronic properties similar to graphene and is easier to modify than graphene chemically, so it is widely used as the surface of SPR sensor chips coating to improve sensitivity. There are many reports of graphene oxide being used to modify SPR chips to improve sensitivity. However, there are different opinions on the use concentration of graphene oxide, and it needs to be immersed for a long time when preparing graphene oxide-modified sensor chips, which greatly affects the chip fabrication efficiency. In this study, long-chain functionalized PEG was used to modify the surface of the SPR gold chip chemically, and the graphene oxide solution was used to modify the chip by the method of flow scouring. By comparing the refractive index change response signals, it was finally determined that the optimal concentration of graphene oxide was 0.5 mg·mL-1, and the modification time was reduced to less than 20 min. The influence of incident light waves of different wavelengths on the resonance peak of the graphene oxide-modified chip was studied, and the chip’s overall performance was evaluated. The chip’s sensitivity under the incident light wave at 950 nm was 243.2°·RIU-1, and the FOM value was 82.2 RIU-1. This value is 33.3% higher in sensitivity and 36.1% higher in FOM than that of the same chip at the original 800 nm incident wavelength, and it is 4 times in sensitivity and 3.41 times in FOM that of the bare gold chip at 800 nm wavelength. The institute proposed that the rapid preparation of graphene oxide-modified SPR sensor chips has the advantages of low cost and fast fabrication and has broad application prospects in the field of biochemical detection.