Electromagnetically induced transparency(EIT) was studied experimentally in a waveguide system with different coupling strength. A deep-subwavelength EIT element consisting of a comb line and a split-ring resonator was put forward, where the coupling strength was adjusted by changing the distance between the comb line and the split-ring resonator. At the EIT frequency, when the coupling strength becomes weaker, the reflectance is higher, the transmittance is lower and the absorbance is first higher then lower. Weaker coupling creates a narrower transparency window. The slow-wave phenomenon is also observed. The measured group delay time goes up and the slow-wave bandwidth decreases, with the decrease of the coupling strength.