To explore an effective way to prevent and control the hydrogen explosion accidents, closed explosion experiments involving hydrogen-air mixtures were carried out in a 2 m-long cylindrical tube under the influences of mesh aluminum alloys (MAAs) and spherical nonmetallic materials (SNMs). The results show that with the increase of filling diameter, the overpressure of hydrogen-air mixtures under the influence of MAAs and SNMs decreases gradually in general, and the flame velocity shows a same trend. MAAs and SNMs have a promotion/suppressing double functions on the deflagration of hydrogen-air mixtures and SNMs show a better suppressing effect than MAAs. It is also found that the deflagration to detonation transition (DDT) is more difficult achieved for larger filling density and larger filling diameter of MAAs and SNMs. In addition, several different DDT mechanisms are discussed in detail, including DDT caused by Mach-stem reflection and by direct initiation due to shock focusing. Based on a mathematical model, a prediction value of 184.30 kg/m³ (filling density of MAAs) may be satisfy the explosion-suppression evaluation criteria according to the Chinese standard AQ3001-2005. These results provide references for preventing explosions of hydrogen-air mixtures and for optimizing the performance of MAAs and SNMs.