Abstract: To address the challenge that existing environmental simulation equipment cannot achieve continuous coupled control of temperature and pressure across a wide altitude range, a broad-altitude temperature–pressure environmental simulation system was designed and developed. By adopting a staged coordinated pressure control architecture for a wide pressure range and proposing a multi-mode temperature control method, the system achieves temperature-pressure environment simulation for a wide altitude range. Experimental results demonstrate that the system achieves a pressure control range from 5×10⁻⁵ Pa to 10⁵ Pa, with a control accuracy of 0.03% at atmospheric pressure, better than ±0.3% from 5.5 kPa to atmospheric pressure, and better than ±10% from 0.01 Pa to 5.5 kPa. The temperature ranges from –173℃ to +60℃, with a uniformity of ±1℃ in the dense atmosphere region (0–30 km) and ±4℃ in the rarefied atmosphere region (30–80 km). The chamber withstands a low-temperature environment of –100℃ and exhibits a leakage rate below 1.0×10⁻¹⁰ Pa·m³/s, satisfying the requirements for high-vacuum conditions. By integrating the simulation capabilities of a cold black background (equivalent to –173℃) and a controllable temperature–pressure atmosphere within a single chamber, the system achieves continuous and high-precision coupled control of temperature and pressure over a wide altitude range. It thus provides a critical experimental platform for validating thermal protection systems in space vehicles and assessing the environmental adaptability of near-space probes.