Abstract: In this study, nanocellulose was prepared by acid hydrolysis, cellulase enzyme pretreatment, TEMPO oxidation and mechanical fibrillation techniques using commercial southern pine dissolving pulp and bleached eucalyptus pulp as raw materials, respectively. This study intended to provide relatively complete morphological pictures of several kinds of wood nanocellulose including cellulose nanocrystals (CNC) and cellulose nanofibrils (CNF) produced by most commonly used processes. TEM and AFM were applied to provide visual examinations of several nanocellulose samples. Commercial particle sizing instruments were evaluated for quick particle sizing the samples. It was found that CNC were mainly rodlike nano-whiskers with diameter of approximately 20 nm and length ranging from 10 to 200 nm as expected, and CNF were fibril network particles with a diameter ranging from several nanometers to several hundred nanometers, respectively. The instruments based on the centrifuge and a Brownian motion showed good repeatability in particle sizing. Both instruments were well suited to semi-quantitative characterize non network particles even with large aspect ratios such as CNC, but further study is required before they can be used for characterizing network particles such as CNF.