The purpose of this paper is to design a laser scanning system for a high temperature and acidic environment to measure small-scale surface roughness of seabed and to collect information related to calcium carbonate debris. The study comprises two parts. One is to construct the hardware and software of the laser scanning system. Two is to test the system at sea. The system were tested at Kuishantao sea area, an area with many submarine springs. The temperature of the hot water from the submarine springs can be as high as 126¢XC. Key substances from this type of hot springs are surfur and air bubbles composed of CO2, N2, O2, SO2, and H2S. These chemicals make the sea water in this area acidic, and the pH value can be less than 2. In other words, this sea area is a high temperature and very acidic environment According the acidic resistant test result, the researchers decided to use Polypropylene (PP) as the material. The laser scanning system captures information automatically, and it uses industrial single board computer (PC104) as the control platform. The researchers selected red laser, which is monotonous, directional, and coherent Lithium batteries, can be recharged repetitively, were used to supply the power. High-precision positioning, high resolution, and with easy speed and angle control stepping motors were chosen for the system. For the software, the researchers chose the Window operating system. The hardware and software of this system are highly compatible. Operating the system is very intuitive because windows are used as the interface, and the hardware has high supporting capacity. This arrangement makes data analysis later on very convenient. Images acquired from conducting the actual experiment at sea that need to be processed. A CCD camcorder with fixed location and angle was used to capture images. With the high brightness characteristic of laser and simple threshold values for screening, the researchers got the pixel position of laser beans. Then a calibrated the camcorder was used to switch the pixel coordinates to obtain the actual size of the object.