With accelerating the miniaturization process of electronic devices, multifunctional optoelectronic devices that increases the compactness between the integrated devices have attracted much attention. In this work, we prepared a 1.0 cm2 two-dimensional Bi2Te2.7Se0.3 material by pulsed laser deposition technology, and fabricated Pd/Bi2Te2.7Se0.3/SiO2/Si multifunctional optoelectronic devices. Under the light illumination, the electron separation and aggregation at the Bi2Te2.7Se0.3/SiO2 interface lead to reducing a lower interface barrier. Meanwhile, electrons in the narrow-bandgap Bi2Te2.7Se0.3 photosensitive material easily escape from shackles and are trapped at the Pd/Bi2Te2.7Se0.3 surface, resulting in the resistance switching for monolithic devices. In addition, the capture of electrons at the interface enables the device to achieve long-term storage of information. The device can perform single functions of logical sum calculation (“OR” gate), multilevel information storage, photodetection and optical information demodulation. Meanwhile, the device might simultaneously implement photodetection and demodulation, logical calculation and memory, and demodulation and storage functions, which will increase the compactness of integrated circuits and reduce power consumption.