Wetlands in arid regions play crucial roles in carbon storage and ecosystem stability, yet the assembly mechanisms of their soil bacterial communities and the underlying drivers remain insufficiently understood. This study systematically investigated the assembly processes of soil bacterial communities across five natural wetlands along the southern margin of the Tarim Basin, China, through field sampling and high-throughput sequencing of the 16S rRNA gene. Our findings demonstrate a clear spatial dichotomy in assembly mechanisms. Deterministic processes (contributing 54.29-86.67%) dominated community assembly in the wetlands of Qiemo, Minfeng, Hotan, and Yecheng counties. In stark contrast, stochastic processes (93.34%), primarily dispersal limitation and drift, prevailed in the saturated wetland of Makit County(soil water content = 70.01%). Specialists, characterized by higher alpha-diversity and narrower niches, played a pivotal role in maintaining network complexity and facilitating the flow of materials and information between modules. Conversely, in the high-moisture environment of Makit County, generalists formed an exclusive network of positive interactions (100%), significantly enhancing network robustness and demonstrating a unique stabilizing function. Analysis of environmental drivers identified mean annual precipitation as the primary factor governing bacterial diversity and composition, while soil pH was the key variable shaping co-occurrence network architecture. Random forest modeling further corroborated that bacterial alpha-diversity and community composition were the optimal predictors of the assembly processes. This study elucidates the relative contributions of deterministic and stochastic processes to bacterial community assembly in arid wetlands of the southern Tarim Basin and reveals the complementary ecological strategies of microbial functional groups (generalists vs. specialists) in maintaining ecosystem resilience. The findings provide a scientific foundation from a microbial perspective for the ecological conservation of arid wetlands.