This paper is intended to examine changes in the microstructure and crystal orientation of 7055 aluminum alloy before and after cutting. Single-factor cutting speed test was designed and implemented to investigate the influence of three heat treatment processes, T6, T87 and T815, on the microstructure and crystal orientation of 7055 aluminum alloy before and after cutting. Results showed that, before cutting, T6-state microstructure had uniform grain size with pinning in θ′ phase; T815-state grains were obviously elongated as a result of predeformation; T87-state grains also displayed some elongation, but their overall elongation was not as long as that of T815-state grains; there was a dislocation in the TEM microstructure after both T87 and T815. After cutting, T6-state initial grains were elongated; their horizontal and longitudinal sizes were 46 and 92 μm, and the low-angle boundary (LAB) and high-angle boundary (HAB) densities of T6, T87 and T815-state grains were $$1. 8 5\times 10^{ - 1}$$ , $$3. 2 5\times 10^{ - 2}$$ , $$1. 2\times 10^{ - 1}$$ , $$2. 2\times 10^{ - 2}$$ , $$2. 5\times 10^{ - 1}$$ and $$4. 3\times 10^{ - 2}$$ μm−1. The crystal structure and orientation relationship of T6-state alloy after aged for 4, 8 and 12 h was θ′′, θ′, and many mixed regions of θ′′ and θ′, were observed along {001}α. After aged for 12 h, the T8-state microstructure along [001]α and [011]α was roughly the same as that after aged for 4 h, except that the share of θ′ particles along [011]α had increased from 55 to 90% while θ′′ particles along [001]α had reduced a little. After aged for 12 h, the precipitated particles of the cutting layer of T815-state alloy along [001]α were all θ′ phase while those along [011]α were composed of θ′ and Ω phases. From the boundary microstructure, before cutting, the grain boundary of T6-state alloy was a continuous one with no obvious non-precipitate zone; the grain boundary of T87-state alloy displayed some discontinuity as a result of predeformation, and quite a lot of the precipitated particles were concentrated on the boundary; the grain boundary of T815-state alloy was a discontinuous one, but the non-precipitate zone on the boundary was not as wide as that of T87-state alloy. After cutting, T6-state alloy had the widest non-precipitate zone of all at about 42 nm. The non-precipitate zone of T6-state alloy was 25 nm wide, and the particles were mainly grown θ′ particles, and θ particles incoherent to the aluminum matrix. The non-precipitate zone of T815-state alloy was the narrowest at approximately 15 nm.