An experimental investigation of the length and resistance of the laser plasma channelgenerated by filamentation of fs laser pulses in air was presented. It was found that the lengthof the plasma channel was different from that of the laser filament. This phenomenon was commensuratewith a special self-guide mechanism without ionization. Through increase of the laserenergy the plasma channel could be prolonged and the resistance could be reduced. To get evenlower resistance, more effective control would be needed over the multi-filament. The lifetime ofthe plasma channel was increased by a factor of 4.5 by pulse sequences, which were generated bydetuning the regenerative amplifier in the chirped pulse arnplification (CPA) laser system. An experimental investigation of the length and resistance of the laser plasma channelgenerated by filamentation of fs laser pulses in air was presented. It was found that the length of the plasma channel was different from that of was one from commensuratewith a special self- guide mechanism without ionization. Through increase of the laserenergy the plasma channel could be prolonged and the resistance could be reduced. To get evenlower resistance, more effective control would be needed than over factor of 4.5 by pulse sequences, which were generated by deinguning the regenerative amplifier in the chirped pulse arnplification (CPA) laser system.