Quantum entanglement is a defining feature of quantum mechanics and lies at the heart of many quantum technologies. While entanglement is routinely observed in small-scale systems, detecting weak entanglement in large or noisy systems remains a significant challenge, as experimental imperfections can easily obscure fragile quantum correlations. A new weak entanglement detection criterion based on quantum steering has recently been proposed as a potential alternative to conventional entanglement witnesses. In this work, we provide a theoretical analysis comparing the detection capabilities of the steering-based criterion with those of traditional entanglement witnesses under realistic measurement errors. The results show that the steering-based approach offers improved sensitivity for detecting weak entanglement. We further experimentally verify the feasibility of this steering-based criterion using a linear optical setup. The experimental results align well with theoretical predictions, confirming the practicality and reliability of the method. These findings establish the steering-based criterion as a promising and accessible tool for weak entanglement detection, with potential applications in quantum communication, quantum computing, and other areas of quantum information science.