Initial preparation of sea weed from Krakal beach and Lemah Abang Jepara. The Sea Weed from Krakal beach, Gunung Kidul, and Lemah Abang, Jepara have been prepared. The sea weed was initial prepared by crushed, dryed by freeze dryer, milled using a ball-mill and sieved with unscreened grain size of 100 mesh. The homogenized powder were tested by Laser Particle Sizer Analysette 22, by double preparation and four times measurement for every sample. The grain size of both powder was in the range of 4.623 um to 583.015 um, arange in 31 classes. The smallest class were the particles with size 4.623 – 5.462 um. The second class having the lowest size 5.462 um, the midle size was 5.96 um, and the highest was 6.453 and so on. The largest class has the smallest size 493.445 um, the midles size 538.23 um, and the largest was 583.015 um. The geometric mean diameter of the Sea Weed from Krakal was 135.667 um, and from Lemah Abang 46.053 um respectively. The Krakal Sea Weed's curve showed that the skewness was 0.839, kurtosis 0.950, and Specific Surface Area was 0.08 m² mL-1, and from Lemah Abang the skewness was 1.921, curtosis 7.133, and the specific surface area was 0.23. The curves of cummulative percentage versus particle sizes showed that the eighth curves were relatively identic and close together, showed that the powder were physically homogen, and may be continued to the chemical analysis.