TeV gamma rays will be attenuated or absorbed due to the interaction with s
oft photons in intergalactic space. The spectra of Mrk421 and MrK501 during
their flaring have been observed by ACTs. Using the data obtained with Tib
et Il IHD AS array from October of 1995 to Augest of 1997,the preliminary r
esults of energy density of intergalactic infrared radiation field are pres
ented in this paper. Analysis shows that no statistically significant absor
ption evidence of high energy gamma rays is found up to around 30 TeV.