The invention discloses a method for manufacturing a T-shaped grate by utilization of deep-UV lithography, comprising the following steps that: a substrate is cleaned and dried and then coated by chemical amplifying deep-UV photoresist; contraposition, alignment, exposure and development are performed by adoption of a deep-UV exposure machine, and a grate root photoresist window graph is formed initially; the photoresist window graph which is formed by exposure is shrunk by adoption of chemical shrinking solution; electron beam slushing compounds are coated; chemical amplifying deep-UV photoresist is coated; contraposition, alignment, exposure and development are performed by adoption of the deep-UV exposure machine; exposure and development are performed by adoption of deep-UV electron beam slushing compounds, and a grate cap photoresist window graph is formed; grate electrode metals are deposited by adoption of the metal evaporation method; the metals are peeled off and the photoresist is stripped, and then manufacture of the T-shaped grate is finished. The method makes a grate root of the T-shaped grate break through the manufacturing limit of superfine lines of a photoetching plate, saves the manufacturing cost of the photoetching plate and simultaneously can realize large-scale deep-submicron processing of compound semiconductor devices.