Abstract: The planar “two-dimension isochronous time-of-flight (2DisoTOF)” is a new type of multiple-reflection time-of-flight mass analyzer. It is composed of a series of flat plate electrodes arranged in parallel, boasting advantages such as simple structure, compact size, and high mass resolution. In this study, a 2DisoTOF model with new structural parameters was constructed through simulation, in which the electrode length in the Z-direction was extended to 1 000 mm based on the original structure. This aimed to effectively lengthen the ion drift path, thus significantly increasing the flight time of ions within the analyzer to achieve a higher mass resolution. After the model construction, its analytical performance was investigated by simulation. Firstly, the cooling conditions of the ion introduction device in the front-end were optimized, and the cooling effects on ion kinetic energy under the conditions of using air and helium as the cooling gas were studied respectively. Compared with the results when helium was used as the cooling gas, it was proved that air could more effectively reduce the ion kinetic energy than helium. Secondly, The voltage parameters of the mirror electrodes were investigated, and the magnitude relationship between the first-order focusing voltage difference ∆V₁ and the second-order focusing voltage difference ∆V₂ was studied. By evaluating the trajectory width of ions reaching the detector focal plane, the optimal value of the voltage V_X0 on the mirror electrode X0 in the drift direction was obtained, and the values of ∆V₁ and ∆V₂ were optimized respectively. It was demonstrated that when V_X0=24 V, ∆V₁=13 V, and ∆V₂=11 V, the highest mass resolution obtained can reach 168 576. Additionally, the influence of ion number and charge on the mass resolution was studied with consideration of the space charge effects. The simulation results showed that when the ion number or charge increased, the mass resolution decreased accordingly. This degradation was attributed to the intensified electrostatic repulsion among ions at elevated densities and charge states, which led to the ion self-bunching and the neighboring mass peaks coalescence, consequently compromising the mass resolution. Compared with the influence caused by increasing the ion charge, the negative effect of the increasing ion number on the mass resolution was more significant. However, even under the circumstances of large number of ions with highly charged, the 2DisoTOF could still achieve a high resolution exceeding 20 000, suggesting that this type of mass analyzer possesses significant performance potential. This provides a solid theoretical basis and practical reference for future optimization and practical applications of 2DisoTOF mass analyzer.