A new high-speed spinning disk reactor (HSSDR) was proposed and tested successfully. In this regard, barium sulfate (BaSO4) nanoparticles were synthesized using reactive crystallization processes. In this reactor, the rotational disk speed was varied from 5000 to 15 000 rpm. The effects of various design and operating parameters such as the rotational disk speed, feed entrance radius, volumetric flow rate of feed solutions, supersaturation, and free ion ratio were investigated in detail. The mean particle size (MPS) and specifications of the synthesized barium sulfate were investigated using scanning electron microscopy combined with energy-dispersive X-ray spectroscopy and powder X-ray diffraction. Nanoparticles with smaller MPS and narrower particle size distribution (PSD) were synthesized due to an increased micromixing obtained in the HSSDR Moreover, BaSO4 nanoparticles with the MPS of 16.4 nm and PSD of 4-26 nm were synthesized successfully. This clearly shows that the proposed reactor is a promising contacting device in process intensification.