Nowadays, the most prevalent method to measure the distance from the terminal to the receiver and to position the receiver is based on the correlation character of Pseudo-random-noise code (PN code) carried on GPS signal. And the basic of positioning is the measuring. However, the probability of the measuring with GPS signal in the metropolis area is almost equal to 0% due to it sheltered and interference. Launchers of digital television have already built in many cities of our country as the one fundamental establishment of metropolis. The sent signal from launchers is powerful in power, low in frequency and wide in bandwidth, and also covers absolutely entire city including many building dense areas. In this paper the signal frame structure of digital television terrestrial broadcasting (DTMB) standard of our country named GB20600-2006 is analyzed. Then the scheme measuring the distance with the special discontinuous PN code in the DTMB signal is designed. At last the practical distance from the terminal to the receiver in Xi`an is measured by this scheme. The analysis of the measurements is shown that measuring with this scheme is feasible. And it provides the technology basic to positioning and navigation especially in the metropolis.