The invention discloses an on-site installation method for a suspension type valve tower. Firstly, a hoisting device is used to lift a top valve group of a valve tower to a pre-set height. The pre-set height is a height allowing a first lower valve group in close to the top of the valve tower to be arranged under the top valve group by workmen on ground. The hoisting device then raises the top valve group step by step and during the lifting process, the workmen on ground put the rest lower valve groups in series connection successively from the top to the bottom, all under the first lower valve group. Finally, the hoisting device continues lifting the top valve group to a height where the top valve group can be fixedly connected to the lower end of a suspension connection structure of which the top end is fixedly connected to a top steel beam of an on-site building and the top valve group is fixedly connected to the lower end of the suspension connection structure. The installation method is very effective and workmen do not have to spend much time at height, therefore, construction difficulty and construction risk can be reduced. At the same time, the method does not require rich altitude working experience from workmen, lowering the threshold for people who do such a job.