The increasingly stringent national regulations have imposed restrictions on the weight compliance of concrete pump trucks. Through multi working condition topology optimization design and model fusion reconstruction technology, a lightweight design was carried out on the boom structure of a certain type of pump truck, achieving a weight reduction of 300 kg. The pioneering reliability assessment verification for the novel “hollow-out” boom structure has been conducted, representing a significant milestone in the industry. The test results show that, the static stress does not exceed 580 MPa, meeting stringent material usage requirements; the fatigue life is equivalent to 9,600 h, surpassing the industry benchmark of 8,000 h. The groundbreaking findings have been successfully integrated into multiple pump truck products, promoting the ongoing advancement of boom lightweight design practices within the industry.