Tight oil and gas reservoir have the characteristics of diverse reservoir properties, vertically stacked multiple layers, thick reservoirs, and low single-well productivity [1, 2]. Multi-layer commingled production and hydraulic fracturing technology are important means to achieve efficient development of tight oil and gas resources [3]. Currently, multiple tight gas fields in the United States, Canada, China, and other regions adopt the method of multi-layer commingled production [4]. Due to reasons such as interlayer thickness and reservoir property differences, different gas supply laws exist between different development layers, leading to a certain degree of interlayer interference. At present, the specific contribution characteristics of small layers in multi-layer commingled production are not very clear. Field test data indicates that due to interlayer heterogeneity, the gas production contribution capabilities of various small layers in multi-layer gas reservoirs differ significantly, and these contributions also change over time. To address the above issues, based on the flow characteristics of multi-layer gas reservoirs, an unstable flow model considering reservoir property differences in multi-layer gas reservoirs was established and solved using Darcy's law and the source function method. The changing characteristics of layered production contribution rates for multi-layer commingled wells with hydraulic fracturing in tight gas reservoirs were calculated. When not considering the effects of wellbore storage and skin effect, before the pressure wave propagates to the boundary, the contribution of each layer is approximately equal to the coefficient ratio of the formation. When the pressure wave propagates to the boundary to form quasi-steady flow, the contribution of each layer is approximately equal to the ratio of their storage capacities [5]. The existence of skin factor makes the contribution of each layer no longer approximately equal to the formation coefficient ratio or storage capacity ratio. Generally speaking, layers with larger skin factors will have lower production contributions, while layers with smaller skin factors will have higher production contributions. This research outcome provides guidance for the dynamic analysis and utilization of small layer reserves in multi-layer gas reservoirs [6].