The field experiment results showed that the watermelon yield could be increased apparently, Se and sugar contains in fruits were also increased. The concentration could be chosen among 45 - 105 times. By 45 times at primary flower and bear fruit stages individually, the increase of yield was 15.10%, the increase of sugar contains was 10.9%, the increase of the Se contain was 795.22% and that of soluble solid was 6.80% compared with the cheek.