The molecular weight and distribution of natural rubber (SCRWF) were changed by mechanical shearing force. Gel permeation chromatography was used to test and demonstrate that the molecular weight and molecular weight distribution of SCRWF changed apparently after treatment. The plastic properties of plasticity initial values (

P

0

)

plastic retention (PRI)

Mooney viscosity and stress relaxation time of different rubber samples were compared and analyzed. The thermal stability

mechanical properties and processing properties of vulcanized rubber were analyzed. The results show that the molecular weight of natural rubber decreases with the increase of mechanical shearing force

and its single peak trend is obvious. The quality of the raw rubber and the thermal stability is greatly affected by mechanical shearing force

and the mechanical properties of the vulcanized rubber are degraded with the increase of mechanical shearing force. Rubber processing analyzer (RPA) analysis shows that the loss factor (tanδ)of the samples increases linearly and the elastic modulus (

G

') decreases linearly with the increase of strain in the strain sweep

the loss factor (tanδ) of the samples decreases linearly and the elastic modulus (

G

') increases linearly with the increase of frequency.