In accordance with the development of our national steel industry, we try to construct a spectroscope for the visual analysis of the compositions of steel or the other alloys. The work is completed in a course of 2 1/2 month. The whole apparatus consists of an auto-collimating spectroscope, a special desgined holder for specimens, and a high frequency activated alternating current are source. The model is somewhat like that produced by the firm of Fuess, but the whole optical systems are designed and computed according to the theory of optical abbora-tions. The auto-collimating objective is made achromatic, and the eyepiece is of Kolner type with magnification of 25X. With one and half prisms, each with 3 cm base, the spectroscope disperses the spectrum from 3900? to 7000?. The li-near dispersions of the final image of the system, at λ = 4358? and λ= 5893? are 0.89?/mm and 2.91?/mm, respectively. The resolving power △λ of the spectroscope at those wave lengths is 0.14? and 0.59?, respectively. The cireuit dia-gram of the arc source is also given.