Abstract: Background: As the first full superconducting non-circular cross section Tokomak in the world, Experimental Advanced Superconducting Tokamak (EAST) is used to explore the forefront physics and engineering issues on the construction of Tokomak fusion reactor. Neutral beam injection has been recognized as one of the most effective means for plasma heating. Purpose: This paper aims to present the latest progresses of EAST neutral beam injector. Methods: Long pulse beam extraction and high power beam extraction were experimentally tested to verify the performance of a set of neutral beam injectors (4–8 MW, 10–100 s) which were developed and put into operation in 2014. Results: Test results showed that beam power and pulse length met or exceeded the design requirments. Conclusion: All these progresses lay a solid foundation for the achievement of plasma heating and current drive for EAST in the future.

Key words: Neutral beam injector, Beam extraction, Ion source