The speaker leads a line survey of TianMa 65 m radio teleacope (TMRT) aimimg to provide an unprecedently sensitive (mK) spectral template covering 1--50 GHz, in preparation for the forthcoming era of low-frequency radio interferometers (e.g., ALMA band 1, SKA). More than one thousand line features were detected from the already accomplished Ka/Q-band (26-50 GHz) pioneer surveys towards Orion KL, including many previously undetected transitions of complex organic molecules (COMs) and radio recombination lines (RRLs). Especially, RRLs of ions heavier than helium were detected for the first time. Those lines were assigned to carbon and/or oxygen with an unprecedentedly accurately measured abundances. This discovery provides a tool of measuring elemental abundances in embedded and obscuered regions. This project demonstrates the huge potential of TMRT, which is the largest steerable radio telescope in Asia but had not been fully used in astrochemical studies. The speaker will present the relevant scientific results, as well as how he and his colleagues optimized the TMRT for deep line surveys.