The shear bond behavior of the flat-type composite deck slab, Econdek65-675 is investigated primarily. Based on the Euro code 4, the relevant value, m-k, is achieved based on the test of 18 composite slab specimens. According to the thickness which is 115 mm, 150 mm and 200 mm respectively, these 18 specimens were divided into three groups with two sets in each group. One set was tested for shorter shear span loading and the other one was set for longer shear span loading. It is shown that the Euro code 4 is more accurate than the American code. Meanwhile, the calculation formula of longitudinal shear resistance of the composite slab as well as its relevant curve is presented. Compared with other similar composite slabs, it is proved that Econdek65-675 possesses reliable composite efficiency.