Flexible thermoelectric materials play an important role in smart wearables, such as wearable power generation, self-powered sensing, and personal thermal management. However, with the rapid development of Internet of Things (IoT) and artificial intelligence (AI), higher standards for comfort, multifunctionality, and sustainable operation of wearable electronics have been proposed, and it remains challenging to meet all the requirements of currently reported thermoelectric devices. Herein, we present a multifunctional, wearable, and wireless sensing system based on a thermoelectric knitted fabric with over 600 mm·s⁻¹ air permeability and a stretchability of 120%. The device coupled with a wireless transmission system realizes self-powered monitoring of human respiration through an mobile phone application (APP). Furthermore, an integrated thermoelectric system was designed to combine photothermal conversion and passive radiative cooling, enabling the characteristics of being powered by solar-driven in-plane temperature differences and monitoring outdoor sunlight intensity through the APP. Additionally, we decoupled the complex signals of resistance and thermal voltage during deformation under solar irradiation based on the anisotropy of the knitted fabrics to enable the device to monitor and optimize the outdoor physical activity of the athlete via the APP. This novel thermoelectric fabric-based wearable and wireless sensing platform has promising applications in next-generation smart textiles.