The extra stator hub blockage results in the axial velocities increasing outboard of the 25% span, which further increases the negative incidence of the rear rotor, reduces the load and the total pressure rise of the blade row. An experimental study of leakage flow from shrouded stator cavity was completed by [PERSON] and [PERSON] [6] in a low speed four stage compressor. In this work it was shown that the increasing seal cavity leakage not only worsens the flow field at the root of the stator row where the leakage flow occurs, but also changes the flow conditions at the stator exit over the entire span. As a result, in the following downstream stage, the work input of the rotor decreases and the total pressure loss of the stator increases, leading to a performance degradation at the next stage. Different from the experimental study of the whole four-stage compressor with multiple cavities, their numerical study was carried out on isentropic stator three and the corresponding cavity. [PERSON] and [PERSON] [7] investigated the interactions between seal cavity leakage flow from the stator shroud and the main flow in a linear compressor cascade and suggested that besides the leakage flow rate, the cavity's tangential velocity is another key factor in the interaction process. The results clearly show that stator performance improves with the increase of the cavity's tangential velocity. Similar results can be found in reference [6; 8; 9]. [PERSON] et al. [10] made an impressive 3D simulation investigating the influence of various shrouded stator cavity geometric parameters on an isolated stator row's performance. In summary, seal cavity leakage flow through labyrinth seal-teeth exists in axial flow compressors with shrouded stator vanes. Although seal-tooth leakage has been shown to have a non-negligible impact on compressor performance, fewer simulations of the compressor together with the seal cavity leakage flow from the shrouded stator are available. In the literature mentioned above, the calculations of compressors with cavity leakage have been simplified to a certain extent. Either the effect of the cavity leakage flow is estimated by using a model, or the cavity is calculated simultaneously with only the isentropic stator. This general lack of simulation tools concerning seal cavity leakage flow from the shrouded stator makes it difficult to visually reflect the effect of seal cavity leakage flow in the design stage of compressor or in evaluating the performance degradation of compressors. In order to provide a computational tool to quickly diagnose the influence of seal cavity leakage flow on compressor performance and internal flow field structure, the circumferentially averaged dimensionality reduction method was used to do the coupling calculation of seal cavity leakage flow and single-stage compressor. As a kind of quasi three-dimensional simulation method, the circumferentially averaged method has its unique advantages. First of all, quasi-3D simulation can provide more abundant S\({}_{2}\) flow field information than 0D simulation. Secondly, quasi-3D simulation is easy to implement due to the small amount of calculation involved. Finally, for specific cases, the quasi-3D simulation can use an empirical model or semi-empirical model, such as a loss model or a blockage model obtained from the experimental data, to modify the flow field results so as to avoid the amplification of the flow field calculation error caused by the limitations of the turbulence model. These advantages make it easier to expand the research work on compressors to entire aeroengine simulations in the future. In this paper, the main passage of a one stage compressor is numerically simulated together with the shrouded stator cavity by an inhouse circumferentially averaged method throughflow program (abbreviated as CAM) which can simulate axial compressors [11], centrifugal compressors, turbines and even combustion chambers [12]. Four configurations, which involved different seal-tooth leakage rates, were simulated.