In order to meet the increasing service traffic requirements of access networks and solve the problem that wavelengths between different passive optical networks cannot be flexibly allocated due to fixed architecture and limited resource dimensions, a time and wavelength division multiplexed passive optical network(TWDM-PON) structure combining lasers emitting fixed wavelengths and optical switch array was proposed. In this new system structure, the downstream wavelength resources were centralized, and the method of configuring the optical switch array at the central office was used to achieve flexible scheduling of wavelengths between different networks. This system can be used to solve the problems such as load balancing, traffic "tidal effect", and low utilization of network resources while reducing overall costs. The feasibility of the system was verified by theoretical analysis and simulation experiments, and the compatibility of the structure with the traditional passive optical network, the sharing of wavelength resources, the low cost of the system, and the characteristics of energy saving were analyzed and demonstrated. Experimental results show that the signal can cover a transmission distance of 30 km without dispersion compensation and can serve 512 users at the same time. This study can provide a reference for passive optical network deployment in typical application scenarios.