The study of microscopic mechanisms of photodissociation and photoionization on small molecules is the major focus in the field of molecular reaction dynamics, which is important from both theoretical and practical aspects. It not only can reveal the physicochemical nature of the interaction between molecules and light, but also can help to understand and eventually regulate the chemical reaction process at the quantum level. This paper systematically reviews the research accomplishments achieved by Academician Zhu Qihe’s group in this field over the years. By utilizing the home-made photofragment translational spectrometers, they have comprehensively explored the photodissociation processes and revealed the microscopic reaction mechanisms for a series of halogenated hydrocarbons in the A band, by measuring the translational energies and spatial angular distributions of the photofragments. They have also investigated the geometric configurations, vibrational spectra, transition energies and ionization energies of benzene derivatives in different electronic states, by using the home-made resonance-enhanced multi-photon ionization and mass-analyzed threshold ionization spectrometers combined with quantum chemical calculations. They summarized the influences of multi-halogen effects, substituent effects and conformational isomerism effects on molecular properties and spectroscopy, supplying important information on the characteristics of excited and ionic states of molecules. These achievements not only deepen our understanding of the microscopic mechanism of chemical reactions, but also provide an important theoretical basis for their practical applications in the fields of atmospheric chemistry, environmental chemistry, biochemistry and material sciences.