My leave and stalk of my Kentia Palm has few problem Please help ！
This looks like leaf miner damage, possibly scale. I am seeing a plant that needs fertilizer, a balanced fertilizer so this plant is able to make its own food as well as be able to fend off insects and disease.
Please send a photo of the entire plant, the pot, the soil and the environment. Is this plant in a pot with potting soil or garden soil? Is there a drainage hole at the bottom of the pot? Is there a layer of gravel or rock between the top of the drainage hole and the bottom of the potting soil? (Not a good thing at all).
Stressed plants are susceptible to insects and disease. Let's check out what caused this plant to be so anemic? Far more important than dealing with secondary issues like leaf miners.
I am thinking you've used garden soil. That would quickly explain where the insects came from. Problem is scooping a scoop of garden soil into a pot is asking for problems. The larger body of soil in a garden contains negative feedback systems to control insects and disease. That soil put in a pot will not have feedback systems. Potting soil has to be sterilized. Potting soil has very little if any actual soil, it is a sterile medium to ensure no wayward disease or insect can become a problem in a pot or planter.
I am also seeing the need for a balanced fertilizer of NPK. Have you used fertilizer of any...sort?
Osmocote 14-14-14 is extended release, use half of what the directions recommend. Another is Dr. Earth's 5-5-5 all purpose fertilizer which is 'organic' and thus extended release as well. If you have used any fertilizer do not add any more until we can help you figure out why your plant is so vulnerable to insects/disease. If you have used potting soil, make sure that we know if that potting soil had added fertilizer, what was added, how long ago a balanced or any solution of anything was added.
Plants in our gardens, plants in pots, plants arranged around our property will always be artificial gardens. That means we humans have to be involved. Educated to be involved because we have to supply the plants we want to grow with everything they need; light, proper water amounts and timing, drainage...medium with drainage, pots with holes, medium in pots has to be sterilized and we humans have to add a balanced fertilizer and know what it is we are adding and why we are adding it to certain plants to fit certain plants needs. "Less is Best, More is Death and None is Dumb" where fertilizer is concerned. Compost is not fertilizer. Compost should never be added to potting soil. Compost is not a soil medium.
Let us know what your maintenance habits are, what fertilizer you've used or have not used, how long you've cared for this palm, what light source this plant is accustomed to, what soil you used in the pot of this palm...this is not at all a death sentence. A wake up call for sure but according to your answers we can set you straight and save your plants.