Orbitronic devices have attracted considerable interest due to their unique advantage of independence from strong spin-orbit coupling. Light metal chromium (Cr), with high orbital Hall conductivity, exhibits significant potential for application in orbit-spintronic devices. In this study, we present experimental verification of the inverse orbital Hall effect (IOHE) in Cr thin films and systematically investigate the underlying physical mechanisms of orbital-to-charge current conversion. The Cr/Ni and Pt/Ni heterostructures were fabricated on Al₂O₃ substrates via magnetron sputtering. Terahertz time-domain spectroscopy was employed to measure the terahertz emission signal. The Cr/Ni heterostructures exhibits the same positive terahertz polarity as the ISHE-dominant Pt/Ni heterostructures, despite the Cr layer owing negative spin Hall angle, which confirms the IOHE of Cr/Ni heterostructure. In the Cr/Ni heterostructures, femtosecond laser excitation generates spin current in the ferromagnetic Ni layer, which is converted into orbital current via its spin-orbit coupling. This orbital current propagates into the Cr layer where it is transformed into charge current through the IOHE. Furthermore, increasing the Cr thickness (2-40 nm) weakens the terahertz emission of Cr/Ni heterostructures due to enhanced optical absorption of Cr layers reducing spin current generation in Ni layers. However, optimizing Ni thickness (3-10 nm) significantly enhances the terahertz emission by improving the spin-orbital conversion efficiency. This work provides experimental evidence for IOHE in Cr films and demonstrates the crucial role of ferromagnetic layer engineering in spin-to-orbit conversion efficiency, offering innovative perspectives for the design and performance optimization of orbitronic devices.